Reinforced rotary brush



April 4, 1961 B. E. NELSON ETAL 2,977,622

REINFORCED ROTARY BRUSH Filed June 10, 1958 INVENTOR. BROOKS E. NELSON RUBEN O. PETERSON ATTORNEYS nited tatcs Patent at high speed.

REINFORCED ROTARY BRUSH Brooks E. Nelson, Chagrin Falls, and Ruben 0. Peterson, University Heights, Ohio, assignors to The Osborn Manufacturing Company, Cleveland, Ohio, a carpora-' tion of Ohio Filed June 10, 1958, Ser. No. 741,125

21 Claims. (Cl. 15 -182) the surface of the work, an improved form of brush for such purpose being disclosed in the co-pending patent application Serial No. 525,224, now Patent No. 2,921,328 of John C. Bongiovanni, filed July 29, 1955, for Rotary Brush With Fluid Passages. Such brushes may be some feet in length and also of quite large diameter so that when operated at high speeds of from, for example, 5,000 to 10,000 surface feet per minute, the brush material is strongly subjected to the action of centrifugal force. We prefer to employ helically wound brush strip which may be of the general type described and claimed in Peterson Patent 2,303,386 wound upon a cylindrical hub, and .under the indicated operating conditions it becomes important that the brush bristle retaining means be capable of withstanding the action of centrifugal force with an adequate margin of safety. The brush strip back will ordinarily be of relatively thin sheet metal shaped to channel form adapted to be circularized so that it may be wound in a closely conforming helix on the cylindrical brush shell or hub. The brush bristle retaining means is conventionally a steel wire extending longitudinally within the channel back of the brush strip and beneath which the brush bristle material (ordinarily crimped steel wire) is doubled. It has been the practice to weld the final turns of the brush strip back to the hub and also to weld the protruding ends of the wire retaining element to the hub. Additionally, end plates provided with axially projecting teeth may be mounted on the hub with such teeth closely overlying such end turns of the brush strip channel back further to secure the latter against radial outward movement or circumferential slippage. As larger diameter brushes are operated at higher and higher speeds and subjected to increasingly severe work, it has become important to provide means'better adapted to secure the brush strip to the hub and to resist the strains to which it is subjected muse.

It is accordingly an important object of this invention to provide improved brush strip adapted to be circularized for mounting on hubs and the like but substantially reinforced to resist the strains to which it may be subjected in use.

Another .object is to provide a power driven rotary brush having a hub with brush strip mounted thereon in a particularly firm and sccure'rnanner to resist the eifect'of centrifugal force when the brush is operated Other objects of the invention will appear as 'the de' scription proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is an elevational view of a power driven rotary brush in accordance with this invention having a large number of turns of helically wound brush strip mounted upon a cylindrical hub;

Fig. 2 is an enlarged fragmentary section through a portion of the cylindrical hub illustrating the manner of securing the final turn of a length of brush strip to such hub;

Fig. 3 is a transverse section taken on the line 3-3 on Fig. 2; and

Fig. 4 is a fragmentary view similar to Fig. 2 showing modified means for securing the end of the brush strip to the hub.

Referring now more particularly to such drawing, the rotary brush of Fig. 1 may comprise a cylindrical hub 1 of the general type disclosed in Bongiovanni application Serial No. 525,224 on which brush strip of the general type disclosed in Peterson Patent 2,303,386 may be helically wound, such brush'strip having a sheet metal channel back 2 within which a layer of brush material 3 is retained by doubling such material beneath an elongated retaining element 4 which in turn is held in place within the brush back by means of teeth 5 and 6 punched in from the respective sides of the back. Adjacent turns of the brush strip may be slightly spaced apart by generally oval flat topped protuberances 7 projecting outwardly from one side of the channel back.

The surface of the cylindrical hub 1 which may, for example, be of aluminum may desirably be provided with a plurality of long lead helical grooves such as 8 to assist in conducting cooling air to the brush strip from the interior of the hub which is connected to such grooves by a plurality of passages (not shown).

Annular end plates or rings 9 and 10 may be mounted on the hub in close lateral engagement with the respective end turns of the helically wound brush strip, such rings being provided with offsets to conform to the helical disposition of such brush strip. The rings may be secured to the hub by means of set screws, for example. Supplementing such rings are inner sheet metal rings 11 and 12 abutting against and conformingto the respective inner faces of heavy end plate rings 9 and 10. Such sheet metal rings 11 and 12 are provided with inwardly projecting teeth (not shown) lying in radial planes adapted to penetrate the brush bristle material 3 and closely overlie the adjacent lip of the end turn of the brush strip back. Such end plates and toothed brush strip retaining ringsare not per se novel and do not themselves constitute a part of this invention.

Before winding the brush strip on the cylindrical hub, the surface of the hub may be coated withadhesive such as a thin layer 13 of epoxy resin composition which may 'be heated and cured after the brush strip has been mounted thereon. Such adhesive affords a very strong bond between the channel back of the brush strip and the cylindrical surface of the hub supplementing the other reinforcing means employed.- Such adhesive, of

course, does not block the ventilating grooves 8 nor pre back 2 is formed be of as thin gauge as feasible, such thinness also facilitating circularization of the brush strip back as it is wound upon the hub. This however, naturally reduces the strength of the back in resisting the action of centrifugal force in use, and we accordingly provide a strip of high tensile steel 14 laid in the bottom of the brush strip channel and optionally bonded to the bottom of the channel back by means of an epoxy resin cement or spot welded thereto at intervals. In some cases, it may be desired to weld such reinforcing strip to the bottom of the brush strip channel back only adjacent the respective ends of the latter. Since the high tensile strip or tape 14 is fiat and relatively thin, it is readily bent when the brush strip back is wound upon the hub.

It is conventional in the manufacture of brush strip to employ an elongated brush material retaining element extending longitudinally within the channel back, such element usually being a wire monofilament. When brush strip is circularized and mounted on a hub in the manner of the present invention, however, such wire is subjected to considerable longitudinal tension and must be secured ordinarily at or near its ends to prevent retraction within the brush back with consequent loss of brush material from the back. Wire monofilaments are quite notchsensitive and are therefore likely to fail when scratched, scored or sharply bent. In accordance with our invention, instead of the usual wire monofilament, we employ a retaining element 4 in the form of high tensile strength stranded aircraft cable, ordinarily twisted steel cable which may be flexed relatively sharply without damage thereto and which will still retain considerable strength even should one or more of the individual strands be severed. To assist in preventing retraction of the cable ends within the brush strip back, copper alloy sleeves such as 15, 16 and 17 may be crimped or compressed on the cable within the channel back where such sleeves will engage the teeth punched in from the channel sides. Of course, the irregular surface of the cable 4 itself assists in inhibiting any tendency of the cable to shift longitudinally within the brush strip back inasmuch as such cable frictionally interengages with the teeth and 6 more effectively than does the usual wire monofilament. The ends of cable 4 extending beyond the ends of the brush strip channel back are passed through apertures 18 in the shell of hub 1, looped through apertures 19 in anchors 20, and the loop secured by means of crimped sleeve 21.

Each such anchor 28 is bolted to a boss 22 by means of a U-bolt 23, the channel back 2 of the brush strip passing under the bend of such U-bolt and being compressed and secured thereby as shown in Figs. 2 and 3. A second U-bolt 24 may similarly compress and grip the brush strip channel back at a point spaced from such first U-bolt. Grooves such as 25 and 26 may be milled in the outer surface of the hub shell where such bolts pass therethrough in order to provide locking recesses into which the deformed brush back is drawn by the bolts.

Now referring more particularly to Fig. 4 of the drawing, the embodiment of the invention there illustrated, while generally similar to that of Fig. 2, utilizes the endmost U-bolt 27 for the purpose of securing the reinforcing s'rip 14 only. Such strip is bent around a pin or spool 28 to afford a thickened end portion which cannot be retracted when bolt 27 has been tightened. A shallow groove 29 may likewise be provided in the outer surface of hub 1 into which the U-bolt 27 may slightly buckle the folded strip 14, further to secure the same.

it will be seen from the foregoing that we have provided a reinforced rotary brush in which the brush strip is mounted on a hub in a manner strongly to resist the action of centrifugal force thereon. Moreover, we provide for securing the brush strip to the hub without the necessity of employing welding which may sometimes tend to damage brush parts and brush bristle material as well as being ditficult when, for example, it is desired to weld a steel brush strip back to an aluminum hub. By using the high tensile strength twisted cable 4 instead of the usual brush material retaining element, we both greatly increase the bursting strength of the brush and also reduce the likelihood of longitudinal slipping of such element within the brush back. This type of retaining element is also particularly suited for securing to the hub in the manner shown in Figs. 2 and 4. Employment of a thin Walled channel back of relatively ductile metal both facilitates circularization of the brush strip and increases the amount of brush bristle fill which can be inserted therein, thereby producing a brush of greater bristle density capable of increased work and having a longer life. The employment of the high tensile strength alloy steel reinforcing strip 14 in the bottom of the channel very greatly increases the strength of the brush strip without decreasing the amount of brush material which may be retained within the channel back, the latter merely being made a little deeper than otherwise. By anchoring the end portions of such reinforcing strip 14 as shown in Figs. 2 and 4, the entire brush strip is likewise firmly anchored without relying entirely on locally securing or gripping the relatively thin and weak sheet metal channel back.

Of course, certain features of the invention are of advantage even when preferred embodiments are not employed. Thus, for example, the compressed sleeves 15, 16 and 17 may be applied with benefit to the usual monofilament Wire retaining element and the U-bolts utilized to compress and secure the extreme end portions of the brush strip back. In fact, the several reinforcing means such as the epoxy resin cement and the bottom strip 14 may be utilized independently of one another athough they cooperate in attaining the result desired. The copper alloy sleeves 15, 16 and 17 are a commercially available product, available under the name of Nicopress manufactured by National Telephone Supply Company of Cleveland, Ohio.

When winding the brush strip upon the cylindrical hub, U-bolt 24 will be applied and tightened before severing the brush strip from the assembling machine, thereby ensuring maintenance of tension in the brush strip as wound and preventing spring-back. It is important that the brush strip be thus wound under very considerable tension so that it will not elongate during operation of the brush and bulge away from the hub or core on which it is seated. Any such bulging results in introduction of destructive forces and produces an inaccurate brushing action. It will be understood that the brush face is trimmed, ground and dressed to a high degree of accuracy, and such bulging cannot be tolerated. It is desirable that the tensioning of the brush strip be willcient to produce a small amount of stretch therein insufficient, however, to stretch the same beyond its elastic limit so that a major portion of its inherent stretchability remains to accommodate differences in thermal expansion between the circularized brush strip back (ordinarily of steel) and the hub (preferably of aluminum). After attaching one end of the brush back to the hub or core, the hub is rotated to pull the brush strip through the assembling machine against sufilcient back tension to accomplish the pre stressing mentioned above. While thus winding the brush strip on the hub, both the bottom surface of the strip and the surface of the hub may be coated with a strong adhesive, preferably of the epoxy resin type. By this means, the channel back becomes adhesively fastened to the hub at all of the lands between the ventilating grooves 8. When sufilcient brush strip has been wound upon the hub, the rotation of the hub is stopped but the tension is maintained. No brush fill material is included in the portion of the channel back overlying the U-bolt holes, or a certain amount of brush material may be removed in this region. The U-bolt 24 is then put in place and the retaining nuts drawn tight to illustrated in Fig. 4 and/or by employment of the sec-' ond U-bolt 23. The sleeves are clamped on the cable 4 to ensure against retraction of the latter into the channel brush back when the cable is subsequently severed.

Thereupon, the tension may be released and the cable 4 severed, inserted through hole 18 and secured to the anchor 20. The brush back 2 and the reinforcing element 14 may likewise'be severed at this time. By placing the brush in an oven for a short period of time, the adhesive may be cured to bond the brush strip to the core. Brushes of the type with which this invention is particularly concerned may be more than two feet in diameter and several feet in length. When such brushes are operated at speeds of, for example, 1,800 r.p.m., the centrifugal force to which the brush strip is subjected is very considerable. The brush must also, of course, withstand the force to which it is subjected by resistance of the work-piece against the brush. We prefer to use channel sides which are of somewhat greater height than the usual in order to gain increased strength without sacrific ing brush material room by increasing the metal thickness.

vOther modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

We therefore particularly point out and distinctly claim as our inventioni 1. A rotary brush having a cylindrical hollow alumi num hub, brush strip tightly helically wound on the cylindrical surface of said hub to form a cylindrical brush face; said brush strip comprising a thin sheet steel channel back, a fiat strip of high tensile steel extending longitudinally within said back against the inner bottom surface thereof, a high tensile stranded steel cable extending longitudinally within said back, and a layer of crimped wire bristle material doubled about said cable and retained in said back thereby, said bristle material extending radially outwardly from the helically wound back to form such cylindrical brush face; an epoxy resin adhesive composition bonding said helically wound brush strip back to the cylindrical surface of said hub; aper- 'tures through said hub adjacent the respective ends of said helically wound brush strip,'the respective end portions of said cable protruding from the ends of said channel back extending through such corresponding apertures and being formed into loops, anchoring means within said hub securing said loops to hold said cable longitudinally tensioned; teeth punched in from the sides of said channel back to overlie and secure said cable, metal sleeves crimped on said cable adjacent said end portions thereof adapted to engage certain of said teeth to assist in preventing retraction of said cable end por- 6 3. The brush of claim 1, wherein said high strip is bonded to said channel back.

4. A rotary brush having a cylindrical hub, brush strip tightly helically wound on the cylindrical surface of said hub to form a cylindrical brush face; said brush strip comprising a thin sheet steel channel back, a flat strip of high tensile steel extending longitudinally within said back fiat against the inner bottom surface thereof, a high tensile stranded steel cable extending longitudinallywithin said back, and a layer of crimped wire tensile bristle material doubled about said cable and retained in said back thereby, said bristle material extending radially outwardly from the helically wound back to form such cylindrical brush face; means anchoring the ends of said cable protruding from said channel back to said hub to maintain said cable under tension; and U-bolts spanning the respective end portions of said high tensile steel strip effective to secure the same to said hub.

5. The brush of claim 4, wherein said high tensile steel strip is bonded to said channel back.

6. A rotary brush having a cylindrical hub, brush strip tightly helically wound on the cylindrical surface of said hub to form a cylindrical brush face; said brush strip comprising a thin sheet material channel back, a

reinforcing strip extending longitudinally within said back against the inner bottom surface thereof, said reinforcing strip being of much smaller dimension radially of the brush than the sides of said channel back, an elongated brush material retaining element extending longitudinally within said back, and a layer of brush material doubled about said retaining element and retained in said back thereby, said brush material'extending radially outwardly from the helically wound back to form such cylindrical brush face; means holding said retaining element within said channel back, and anchoring means securing the respective end portions of said reinforcing strip to said hub.

7. The brush of claim 6, wherein said reinforcing strip is of substantially greater thickness than the sheet maerial of said channel back.

8. A rotary brush having a cylindrical hub, brush I the sides of said back to overlie said element, and metal tions within said helically wound back; recesses in the outer surface of said hub underlying the respective end portions of said channel back, and U-bolts spanning said respective end portions of said back and said cable and high tensile steel strip therewithin in the regions of said recesses effective upon tightening to deform said back,

,cable, and strip toward said recesses to assist in securing them against longitudinal movement relative to said hub.

2. The brush of claim 1, wherein the extreme end portions of said high tensile steel strip protrude beyond the corresponding ends of said channel back and are folded over pins, and U-bolts securedv in said hub span such folded portions of said high tensile steel strip and firmly anchor the same against longitudinal withdrawal.

sleeves crimped on the 'end portions of said element adapted to engage certain of said teeth to assist in preventing retraction of said cable'end portions within said helically wound back, said brush strip being secured to said hub.

9. The brush of claim 8, wherein said retaining element is a high tensile stranded cable.

10. In a brush element comprising an elongated sheet material channel back and a layer of brush material secured therein and protruding therefrom; a separate reinforcing strip of high tensile strength extending longitudinally within said back continuously against the inner bottom surface of said channel and lying within the bottom portion of said channel only, said reinforcing strip being of much less outward extent than the sides of said back.

11. The brush element of claim 10, wherein said reinforcing strip is of rectangular cross-section.

12. The brush element of claim 10, wherein said re inforcing strip is of substantially greater thickness than said sheet material of said channel back.

13. In a brush element comprising an elongated sheet 7 material channel back and a layer of brush material secured therein and protruding therefrom; a reinforcing strip of high tensile strength extending longitudinally within said back against the inner bottom surface of said channel, said reinforcing strip being of much less extent than the sides of said back, wherein said channel back is of thin sheet steel, and said reinforcing strip is of high tensile strength steel of rectangular crosssection of substantially greater thickness than said back.

14. In a brush element comprising an elongated sheet material channel back and a layer of brush material secured therein and protruding therefrom; a reinforcing strip of high tensile strength extending longitudinally within said back against the inner bottom surface of said channel, said reinforcing strip being of much less extent than the sides of said back, wherein said channel back is of thin sheet steel, and said reinforcing strip is of high tensile strength steel of rectangular cross-section of substantially greater thickness than said back, and said brush material is secured within said channel back by a high tensile stranded cable extending longitudinally there:

within and teeth punched in from the sides of said channel closely overlying said cable. a

15. A brush element comprising an elongated sheet metal channel back, a high tensile stranded cable extending longitudinally therewithin, and brush material doubled about said cable and retained in said back thereby, said brush material protruding from the channel mouth, teeth punched in from at least one side of said channel closely o"erlying and securing said cable, said teeth lying in planes normal to the sides and bottom of said channel and also acting frictionally to resist relative longitudinal movement of said cable, and sleeves affixed to said cable adapted to engage certain of said teeth to prevent relative longitudinal movement of said cable.

16. In a brush element having an elongated channel back, an elongated'brush material retaining element disposed longitudinally Within said back, brush material doubled about said retaining element and extending outwardly from the mouth of said channel, and teeth projecting inwardly from at least one side of said channel closely overlying said retaining element; stop means secured to said retaining element adapted to engage at least one said tooth to inhibit relative longitudinal movement of said retaining element.

17. The brush element of claim 16, wherein said retaining element is of metal filamentous material, and said stop means is a sleeve secured thereto.

18. The brush element of claim 16, wherein said stop means are secured to said retaining element adjacent the respective ends of the latter.

19. In a brush element comprising an elongated sheet material channel back and a layer of brush material secured therein and protruding therefrom; a reinforcing strip of high tensile strength extending longitudinally within said back continuously against the inner bottom surface of said channel and lying within the bottom portion of said channel only, said reinforcing strip being of much less outward extent than the sides of said back and being bonded to such bottom surface.

20. A rotary brush having a cylindrical hub, brush strip tightly helically Wound on the cylindrical surface of said hub to form a cylindrical brush face; said brush strip comprising a thin sheet material channel back, a reinforcing strip extending longitudinally Within said back against the inner bottom surface thereof, said reinforcing strip being of much smaller dimension radially of the brush than the sides of said channel back, an elongated brush material retaining element extending longitudinally within said back, and a layer of brush material doubled about said retaining element and retained in said back thereby, said brush material extending radially outwardly from the helically wound back to form such cylindrical brush face; means holding said retaining element within said channel back, and anchoring means securing the respective end portions of said reinforcing strip to said hub comprising clamping means on said hub overlying said reinforcing strip in regions where the end portions of the latter are folded back on themselves about spreading means to afford end stop portions.

21. A rotary brush having a cylindrical hub, brush strip tightly helically wound on the cylindrical surface of said hub to form a cylindrical brush face; said brush strip comprising a thin sheet material channel back, a reinforcing strip extending longitudinally within said back against the inner bottom surface thereof, said reinforcing strip being of much smaller dimension radially of the brush than the side." of said channel back, an elongated brush material retaining element extending longitudinally within said back, and a layer of brush material doubled about said retaining element and retained in said back thereby, said brush material extending radially outwardly from the helically wound back to form, such cylindrical brush face; means holding said retaining element within said channel back, and anchoring means securing the re spective end portions of said reinforcing strip to said hub comprising clamping means on said hub overlying said reinforcing strip in regions where the latter overlie recesses in said hub effective to deform said reinforcing strip toward such recesses.

References Cited in the file of this patent UNITED STATES PATENTS 2,553,748 Carlson et al. May 22, 19 51 2,609,242 Nelson Sept. 2, 1952 2,787,017 Abbrecht Apr. 2, 1957 2,821,729 Van Clief Feb. 4, 1958 2,907,063 Jones Oct. 6, 1959 FOREIGN PATENTS 911,362 France Mar. 11, 1946 

